Alcohol separation process

Abstract

The process involves the separation of monohydric and polyhydric products from a liquid homogeneous mixture obtained from the reaction of hydrogen and oxides of carbon in a solvent solution containing a Group VIII metal carbonyl complex catalyst by extracting said solvent solution with a liquid polyhydric alcohol having at least four carbon atoms and at least four hydroxyl moieties at a temperature of at least 50 DEG C. Further, the process is advantageous in that it can be effected under pressure in the presence of oxides of carbon.

What is claimed is: 
     
       1. A process for separating alkane polyol from a liquid phase homogeneous mixture obtained from a homogeneous liquid phase reaction of oxides of carbon and hydrogen to produce alkane polyol, said liquid phase homogeneous mixture comprising alkane polyol, production solvent and catalyst comprising rhodium, ruthenium or cobalt as the carbonyl complex, wherein said production solvent is a solvent for rhodium, ruthenium or cobalt of the catalyst, said process comprising: (a) extracting at a temperature of at least about 50° C., alkane polyol from said liquid phase homogeneous mixture by contact with an extraction solvent of polyhydric alcohol having at least four carbon atoms and at least four hydroxyl groups, such that two liquid phases are formed, one phase containing the greater concentration of alkane polyol and extraction solvent and the other phase containing the greater concentration of production solvent and the greater portion of rhodium, ruthenium or cobalt of the catalyst,   (b) separating phases, and   (c) recovering alkane polyol from the extraction solvent-containing phase.   
     
     
       2. The process of claim 1 wherein the concentration of rhodium, ruthenium or cobalt of the catalyst in the extraction solvent-containing phase is less than 50 ppm. 
     
     
       3. The process of claim 1 wherein said production solvent also contains monohydric alcohols. 
     
     
       4. The process of claim 1 wherein said extraction solvent has one hydroxyl per carbon atom. 
     
     
       5. The process of claim 2 wherein said extraction solvent is sorbitol. 
     
     
       6. The process of claim 1 wherein said production solvent is a crown ether. 
     
     
       7. The process of claim 6 wherein the crown ether is 18-Crown-6. 
     
     
       8. The process of claim 1 wherein the process is carried out in the presence of a carbon monoxide-containing gas. 
     
     
       9. The process of claim 8 wherein hydrogen is present. 
     
     
       10. The process of claim 1 wherein rhodium is contained in the production solvent. 
     
     
       11. The process of claim 1 wherein ruthenium is contained in the production solvent. 
     
     
       12. The process of claim 1 wherein cobalt is contained in the production solvent. 
     
     
       13. The process of claim 10 wherein the alkane polyol comprise ethylene glycol.